INTEGRATION OF ECOSYSTEM THEORIES: A PATTERN

Transcription

1 INTEGRATION OF ECOSYSTEM THEORIES: A PATTERN

2 Ecology & Environment Volume 1 1. S.E. J0rgensen: Integration of Ecosystem Theories. A Pattern ISBN S.E. J0rgensen: Integration of Ecosystem Theories: A Pattern - Second Revised Edition ISBN Hb: ; Pb X 2. F. Klijn (Ed.): Ecosystem Classification for Environmental Management. ma ISBN KLUWER ACADEMIC PUBLISHERS - DORDRECHT / BOSTON / LONDON

3 Integration of Ecosystem Theories: A Pattern Second Edition by Sven Erik j0rgensen Royal Danish School of Pharmacy, Department of Environmental Chemistry, Copenhagen, Denmark SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

4 Library of Congress Cataloging-in-Publication data is available. ISBN DOI / ISBN (ebook) Printed on acid-free paper All Rights Reserved 1997 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 1997 Softcover reprint of the hardcover 2nd edition 1997 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic and mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

5 Contents Preface, First Edition, 1992 ix Preface, Second Edition, 1997 xi 1 INTRODUCTION: RECENT TRENDS IN SCIENCE 1 How Did It start? 1 Physics versus Ecology 3 Ecology and Physics 4 Recent Trends in Science 6 The Ecosystem as an Object of Research 9 2 DO WE NEED A NEW, HOLISTIC ECOLOGY? 13 Two Ecologies 13 Complexity of Ecosystems 18 Ecology and Quantum Theory 38 Holism versus Reductionism 42 3 MODELS IN ECOLOGY 47 Modelling in Ecology 47 Modelling Elements 48 The Modelling Procedure 52 Types of Models 60 Complexity of Models 63 Modelling Constraints and Recent Developments in Ecological Modelling 68 Application of Models as Scientific Experimental Tools 71 4 ENERGY AND ECOLOGY 75 Conservation of Energy and Matter 75

6 VI Energy Flows in Ecosystems 83 The Maximum Power Principle 87 Embodied Energy/Emergy 93 5 ENTROPY AND ECOLOGY 97 The Second Law of Thermodynamics Applied to Ecosystems 97 Information and Entropy 100 Ecosystems Generate Entropy 103 Ecosystems are Non-isolated Systems 106 Energy Sources and Sinks Establish Order 113 Self-organization 121 The Maximum Entropy and Maximum Energy Dissipation Theory EXERGY AND ECOLOGY 131 The Application of Exergy in Ecological Thermodynamics 131 Exergy and Information 135 Application of the Third Law of Thermodynamics to Ecosystem Theory 141 Application of Exergy in Ecosystem Theory and Darwin's Theory 144 Computation of Exergy 150 Exergy and Modelling 159 The Tentative Fourth Law of Thermodynamics NETWORK AND HIERARCHICAL CONCEPTS OF ECOSYSTEMS 175 Networks in Ecology 175 Network Concepts 176 Hierarchical Theory of Ecosystems 180 Network Thermodynamics UTILITY THEORY, INDIRECT EFFECT AND ASCENDANCY 193 Towards a Wider Application of Network Theory 193 Energy Transfer and Utilization Coefficients in Networks 195 Indirect Effects in Networks 202 Ascendancy 214

7 9 CATASTROPHE THEORY AND ECOLOGY 223 What is Applied Catastrophe Theory? 223 Application of Catastrophe Theory to Explain Shifts in Oxygen Concentration as a Function of Time in a Stream 225 Application of Catastrophe Theory to a Lake Ecosystem 230 General Application of Catastrophe Theory in Ecology 238 Ecosystems and Catastrophe Theory 240 vii 10 CHAOS, FRACTALS AND ECOLOGY 247 Introduction and Definitions 247 Bifurcation and Fractal Dimension 249 Ecological Implications 253 Parameter Estimations and Chaos ECOSYSTEM HEALTH 265 Ecosystem Health and Integrity 265 Ecosystem Integrity and Environmental Changes 266 Exergy, Structural Exergy and Buffer Capacities as Ecological Indicators 269 A Practical Procedure to Assess (Partially) Ecosystem Health 272 Assessment of Ecosystem Health: A Lake Ecosystem Example 273 Agro-ecological Sustainability and Ecosystem Maturity DEVELOPMENT OF ECOSYSTEMS 281 Development and Evolution of Ecosystems 281 Development (Growth) of Ecosystems 281 Response of Growth to Seasonal Changes 286 Ecosystem Properties DYNAMICS OF ECOSYSTEMS 295 Ecosystem Dynamics 295 Modelling Structural Dynamics 295 Constraints on Ecological Parameters 299 Application of Exergy as a Goal Function in Ecological Modelling 302 Structural Dynamic Models of Ecosystems 306

8 viii The Intermediate Disturbance Hypothesis (IDH) and Structural Dynamic Models 318 Structural Dynamic Models in Population Dynamics 323 Conclusions GOAL FUNCTIONS, ECOLOGICAL INDICATORS AND ORIENTATORS 327 Introduction 327 Review of Goal Functions 328 Comparison of Goal Functions by the Application of Models 330 Other Comparisons of Goal Functions/Ecological Indicators 335 Cosmological Considerations 336 Exergy Storage/Exergy Destruction 337 Conclusions A TENTATIVE PATTERN OF ECOSYSTEM THEORIES 343 Presentation of a Pattern 343 A Central Law of Ecosystem Theories 344 Relations to Other Theories 351 Tools: Networks and Models 354 Propositions and Ecosystem Properties 356 The Application of the ELT in Specific Cases EPILOGUE 365 APPENDIX 1. DEFINITIONS OF CONCEPTS 367 REFERENCES 369 INDEX 387

9 Preface, First Edition, 1992 Ecosystems are stili a puzzle for mankind. We would like to be able to know their reactions and control them, but repeatedly we have been surprised by their unexpected reactions to our somewhat hasty actions. We unfortunately have to admit that our present knowledge about ecosystems and their true nature is rather limited. Many excellent contributions to a more profound understanding of ecosystems have been launched during the last two decades, but if you do not know the field, it looks as if all the presented ecosystem theories are in complete discord with each other. However, ecosystems are extremely complex and only a pluralistic view will be able to reveal their basic properties. The different approaches have therefore much more in common, when you go deeper into the core material, than the first superficial glance will be able to tell and there is therefore a natural need for a unification of the various approaches to ecosystem theories. It has for many years been my desire to attempt to make a unification of the many excellent thoughts, ideas and observations about ecosystems, that scientists have contributed. These thoughts, ideas and hypotheses have not been made in vain. They all contain a part of the truth about ecosystems and I have felt that it was almost my duty to attempt to find the 'red thread' in all these important contributions to science. It is the aim of this volume to attempt to integrate all these contributions into a beautiful pattern, which will form a tentative comprehensive ecosystem theory. It may contain artifacts, it may in some, hopefully minor, parts be completely wrong, but it will have the strength of being one unifying, comprehensive theory, based upon the many fruitful results already attained, and it can therefore serve as a reference framework for further contributions and ideas in ecosystem theory. It is my ambition that this volume will synthesize the already existing theories in one unifying theory, which can serve as a platform for discussion and further progress of ecosystem theory. I hope that I am thereby contributing to the development in our understanding of ecosystems, because that is urgently needed here and now due to the many immense, apparently incalculable global problems, which mankind is facing and which call for a solution in very few years. I am grateful to all the contributors to ecosystem theory, i.e., all the authors, to whom I refer in the text - see the full list of references. They have all made a smaller or larger piece of the pattern, which I attempt to present as an entity... an almost completed pattern. Without their contributions there would be no pattern, and let me emphasize that the pattern is tentative and only a first attempt to construct a common framework for further development of ecosystem theory. Furthermore, it may be too ambitious a task, but if the 'union of theories' I am

10 x presenting would create discussions, be criticized (heavily), give inspirations to new ideas and thereby changes of the pattern, the aim of this volume has been fulfilled. It should only be considered a first attempt to make a synthesis of already existing material and ideas to contribute to further development by unifying existing ideas instead of presenting a new set of ideas, which would only have added to the confusion. The volume draws heavily of course, on the existing literature about the different presented theories. However, it is attempted to limit the presentation of the theories to the basic ideas, concepts and their ecological implications. It would require several thousand pages to present all details about the various theories. For those who are interested in more knowledge - more details - about a specific viewpoint or theory, it is recommended to go to the basic books or the original references. This volume will only present the core material needed to construct a first tentative pattern of an ecological theory. The book was not written for mathematicians and the mathematics has deliberately been presented not in the most rigorous, but rather in the most accessible form. The aim of the book is to initiate as broad a discussion as possible on ecosystem theory. Many of presented contributions are based upon the application of models. Although models are a powerful tool, they are imperfect. We attempt to capture the characteristic features of natural ecosystems by the use of models, but real ecosystems are far more complex than the models and it is still an open question, as to what this immense complexity implies for the properties of ecosystems. Most ecosystem theorists, however, use models to find model independent properties, i.e., properties that the model possesses independently of the ecosystem being modelled and independently of the complexity of the model, provided it is sufficiently complex to contain the essential features of the modelled ecosystem. I am fully aware of these limitations of models, but we have no other choice today. The excuse for the book should maybe more honestly be formulated and summarized as follows: I have felt deeply in the roots of my soul for at least the last ten years that there is an urgent need for a synthesis, a unification, of existing excellent contributions to ecosystem theories to meet the pluralistic challenges of ecological sciences. So, I had to try to meet this challenge and the result is this book. During the development of this volume I have had opportunity to discuss the content, get fruitful criticism as feedback and be inspired with new thoughts by several of my scientific colleagues and I would like to thank them all for their very valuable support. Listed in alphabetic order, they are: Leif Albert J0rgensen, James Kay, Boris Kompare, Henning Mejer, William Mitsch, S0ren Nors Nielsen, Peter Skat Nielsen, Bernard Patten, J0rgen Salomonsen, Erik Schneider, Milan Straskraba, Peter Symes, Robert Ulanowicz and Richard Vollenweider. Columbus, Ohio, U.S.A. 4. of July 1991 (first draft). Copenhagen, Denmark 21. April 1992 (final text).

11 Preface, Second Edition, 1997 Ecosystem research has developed very rapidly during recent years. It has therefore been necessary to modify and improve the first edition considerably to draw a proper image of the current pattern of ecosystem theories. Several important books have been published in the field since Let me mention a few of the volumes that have contributed considerably to progress in systems ecology: Ecosystem Health, edited by Costanza et al. (1992); Toward a Unified Ecology, by Allen and Hoekstra (1992); Quantitative Ecology, by D.C. Schneider (1994), Modelling and Simulation, by Bossel (1994), Extinction Rates, edited by Lawton and May (1995); Maximum Power, edited by Hall (1995); Species Diversity in Space and Time, by Rosenzweig (1995); Complex Ecology, edited by Patten and J0rgensen (1995); Macroecology, by Brown (1995); The Dynamic Nature of Ecosystems by Pahl-Wostl (1995); Handbook of Environmental and Ecological Modeling, edited by J0rgensen et al. (1996); Ecological Accounting, by H.T. Odum (1996); and Ecology, the Ascendent Perspective, by Ulanowicz (in press). The last mentioned book is an interesting attempt to present the spectrum of ecological theories without mathematics. In addition, numerous papers on systems ecology have been published in various international journals. Both the books and the papers have inspired me in many of the modifications, amendments and improvements implemented in the presentation of the systems of ecological integration and pattern in this volume. Minor changes have been made in Chapters 1, 2, 3, 7 and 8, while important additions and modifications have been made in Chapters 4, 5, 9, 10 and 15 (Chapter 12 in the first edition). Chapters 6 and 13 (previously Chapter 11) have been radically changed to include several new results obtained by the use of exergy, or rather a relative exergy index, as an ecological goal function. Three new chapters have been added: Chapters 11, 12 and 14 in the present edition. Chapter 11 deals with the concept of ecosystem health: can we assess the health condition of an ecosystem by ecological indicators? Chapter 12 focuses on ecosystem development and attempts to unite the thermodynamic considerations presented in Chapters 4, 5 and 6. Chapter 14 is entitled 'Goal functions, ecological indicators and orientators' and attempts to present the parallelism of the different proposed goal functions and to show that they are complementary in the sense that they cover different aspects of the ecosystems. This chapter is considered an important basis for the presentation of the pattern in Chapter 15. I hope that I have been able with this new edition of Integration of Ecosystem Theories: a Pattern to enhance my modest contribution to an integrated ecosystem theory which can be used for a better understanding of ecosystems at the system level, leading thereby to a better management of our environment.

12 xii During the development of this second edition, I have had opportunity to discuss the content, receive fruitful criticism as feedback, and be inspired with new thoughts by several of my scientific colleagues. I would like to thank them all for their very valuable support. Listed in alphabetical order, they are: Robert Costanza, Leif Albert J0rgensen, James Kay, Boris Kompare, Byong Lee, Henning Mejer, William Mitsch, S0ren Nors Nielsen, Peter Skat Nielsen, Bernard Patten, David Rapport, J0rgen Salomonsen, Erik Schneider, Milan Straskraba, Robert Ulanowicz and Richard Vollenweider.